Homicide (Degrees of Murder)

Homicide law categorizes unlawful killings into degrees based on the defendant's culpability. At common law, murder was defined as the unlawful killing of a human being with malice aforethought. Malice could be express (intent to kill) or implied (intent to cause serious bodily harm, depraved heart recklessness, or felony murder). Modern statutes divide murder into degrees to assign proportional punishment.

First-degree murder typically requires a willful, deliberate, and premeditated killing. Premeditation means the defendant thought about the killing beforehand, though the time required for premeditation can be very brief -- some courts hold that even a moment of reflection is sufficient. Deliberation requires a cool and dispassionate decision to kill, as opposed to an impulsive or emotionally driven act. Many statutes also classify certain types of killings as first-degree murder regardless of premeditation, including murder by poison, lying in wait, or during the commission of specified felonies (felony murder).

Second-degree murder is a residual category encompassing all murders that do not qualify as first-degree. This includes intentional killings without premeditation and deliberation, killings committed with the intent to cause serious bodily harm, and killings resulting from extreme recklessness demonstrating a depraved indifference to human life (depraved heart murder). Depraved heart murder applies when a defendant acts with extreme recklessness regarding a risk of death, such as firing a gun into a crowded room. The Model Penal Code does not use the degree framework but instead classifies criminal homicide as murder, manslaughter, or negligent homicide, with murder defined as purposeful, knowing, or recklessly indifferent killing.